Peripheral blood and bone marrow samples are collected periodically for laboratory biomarker studies. Samples are analyzed for surface markers (e.g., CD3, CD4, CD8, CD10, CD19, CD20, CD25, CD38, CD52, Zap-70) and IgVH by PCR, flow cytometry, and FISH. Samples are also analyzed for alemtuzumab and anti-alemtuzumab antibody levels by flow cytometry.